The invention provides a method for shaping hair which comprises subjecting the hair to a series of consecutive treatments, wherein each treatment comprises the following steps:(i) topically applying a hair shaping composition to the hair(ii) allowing the composition to remain on the hair for a period of from 10 to 180 seconds(iii) rinsing the treated hair, and(iv) mechanically shaping the rinsed hair by contacting it with a heated hair shaping device at a temperature of at least 50°Cand wherein the number of consecutive treatments in the series is from 2 to 10and wherein the time interval between each two consecutive treatments in the series is from 8 hours to 30 daysand wherein the hair shaping composition has a pH of 4 or less and comprises from 0.05 to 1.5% (by weight based on the total weight of the composition) of glyoxylic acid or a salt or hydrate thereof.
